Prefabricated double wall concrete components have been used in the past to construct building walls. Such wall members may include a plurality of welded wire spacing frames to retain the slabs of the wall member in a spaced apart configuration. Typically, the welded wire spacing frames provide limited structural reinforcement of the wall member. It has been proposed to use such prefabricated wall members as structural flooring and/or roofing members. However, a dual slab member designed as a wall may not be readily adaptable to a floor or roofing application due to different loading forces on the member. For example, a wall member used in a floor application may have a limited span distance due to the minimum structural capacity provided by the welded wire spacing frames. More robust welded steel trusses having upper and lower longitudinal portions embedded in respective upper and lower slabs have been proposed as a framing structure for a composite truss that can span up to 60 feet and greater. However, the great weight of these large duel panel prefabricated trusses raises problems of lifting and moving the truss without damaging the truss panels. It becomes desirable to incorporate means in a truss during manufacture of the truss for connecting lifting cables or hooks which can support the great weight of the truss. Attaching and/or other structural attachment techniques used to manufacture such framing structures significantly adds to the cost and time needed to manufacture the trusses and thereby increases the cost of the composite truss.
In our prior U.S. Pat. No. 8,667,755 for a Dual Panel Composite Truss Apparatus, a dual panel truss has a pair of spaced apart prestressed concrete panels having a versatile and adaptive structurally supporting end bearing truss on the ends thereof. The end bearing truss incorporates a versatile and adaptive structural support on each end of the composite truss. The end bearing truss is formed as an integral part of the composite truss for supporting the ends of the composite truss when the composite truss is used for the floors and ceiling of a building. The end bearing truss advantageously forms each end of each concrete panel form for the concrete pour when making each concrete panel. This prior patent is an improvement of our prior U.S. Pat. No. 7,891,150 for a Composite Truss by Robert D. Finfrock and Allen R. Finfrock. In this prior patent, a composite truss has a pair of spaced apart prestressed concrete panels and a plurality of substantially vertical members spanning between the pair of spaced apart concrete panels, one end portion of each vertical member being embedded in one of the spaced apart concrete panels and the opposite end being imbedded in the other concrete panel. The truss includes a diagonal member spanning between the one end of a vertical member and the other end of an adjacent vertical member. Each end of the diagonal member non-structurally engages an end of a vertical member. Each diagonal member also has a length thereof embedded in the concrete in each spaced apart concrete panel. Each end of the composite truss has a prefabricated concrete end bearing beam for supporting the end of the composite truss.
Our prior U.S. Pat. No. 8,763,333 is for a method of making a dual panel composite truss having a pair of spaced apart prestressed concrete panels. The process includes assembling the truss frame, which includes interconnecting and mounting a plurality of steel posts and connecting truss members and reinforcing rods, and positioning a truss frame in a panel form having prestressed strands therein for pouring a first prestressed concrete panel on one side of the truss frame. The truss frame with the first concrete panel is then stripped from the form, lifted and placed on a turning table and turned to position the other side of the truss frame in the panel form for pouring concrete into the panel form for pouring the second prestressed concrete panel, which when cured, is spaced from the first panel by the truss frame forming a composite.
In our prior U.S. patent application Ser. No. 14/533,173 for a Truss Lifting Apparatus and Process, a truss lifting system is used for coupling a lifting truss to a load to be lifted and especially for lifting a large prefabricated concrete panel in the making of a dual panel truss having one of a pair of spaced apart concrete panels of a composite truss formed. The lifting process in this application has a lifting truss having a plurality of spaced hydraulic cylinders hanging therefrom with each hydraulic cylinder having a lifting hook attached thereto for attaching to an attachment member on an object to be lifted. The plurality of hydraulic cylinders are actuated simultaneously to pull each coupled lifting hook and attachment member taut and then locked for the lifting truss to lift the attached object.
The present invention is for a system for lifting a complete concrete panel and especially a dual concrete panel truss having two spaced prestressed concrete panels which form a composite truss.